Since citizens of most countries do not need visas to enter Hong Kong, the HKETOs concentrate most of their work on promoting trade and tourism. In countries or territories where no HKETO is present, diplomatic missions of the PRC have the duty to represent Hong Kong's interests. Visa applications at these missions are, nevertheless, sent to and processed by the Immigration Department of Hong Kong.
All HKETOs were placed under the Commerce, Industry and Technology Bureau of the Hong Kong Government. Since the Mainland Affairs Liaison Office (內地事務統籌辦公室) was set up in April 2006 within the Constitutional Affairs Bureau, the HKETO in Guangdong, together with the Beijing Office (which was then under the Office of the Chief Secretary), were transferred the Constitutional Affairs Bureau. The HKETOs in Shanghai and Chengdu set up subsequently are also placed under the Constitutional Affairs Bureau. The HKETOs overseas have remained under the Commerce, Industry and Technology Bureau.
The HKETOs overseas, particularly those in Europe and Asia, have responsibilities for several countries. Those in the mainland similarly have responsibilities across several provinces. The government had also announced its plan to establish an HKETO in Berlin.
Prior to the transfer of sovereignty in 1997, Hong Kong's commercial interests in its major trade markets were represented by Hong Kong Government Offices - consular matters were handled by the relevant British embassy or high commission. By 1982, the Hong Kong Government Offices, with locations in London, Brussels, Washington and Geneva, were placed under the then Councils and Administration Branch (兩局及行政科).
In preparation for the handover, the British and PRC governments agreed that these offices should be renamed "Hong Kong Economic and Trade Offices", to make clear that they did not have diplomatic or consular functions. In the United Kingdom, the Hong Kong Economic and Trade Office Act 1996 conferred a number of personal immunity and tax privileges on the HKETO in London.
Similar arrangements were negotiated with other host countries of HKETOs. For instance, the HKETO in Toronto is accredited by Canada's Department of Foreign Affairs and International Trade under the Foreign Missions and International Organizations Act , and HKETO in Sydney by the Overseas Missions (Privileges and Immunities) Act.